Systems and methods that allow users to interact with computers often rely on manipulating input/output devices (e.g., a mouse, a keyboard, touch screen and the like). Many of these systems and methods identify such interaction from the perspective of the computer, not the user. Other systems that attempt to identify user interaction with a computer (e.g., vision tracking) from the user's perspective can require the user to maintain unnatural posture that is difficult to maintain over extended periods of time. Alternative systems and methods are needed that provide more intuitive user postures and movements for interacting with a computer based on the user's perspective.